I'm using Mandrake (very similar to RedHat). Lynx is /usr/bin/lynx for me.
you can type the full path to lynx, or you can add that path to your $PATH environment variable so you can get away with just typing "lynx <url>"
a more general answer would be "just run a find":
find . -name "lynx"
you'll probably see a lot of useless "Permission denied" and "No such file or directory" output, but if you have lynx installed, you'll see some sort of response in the list that looks like "/yadda/bin/lynx". that's probably the path to your proggie.